Sitting in traffic, smelling everyone else’s exhaust (you know yours doesn’t stink), you begin to worry about the bees out there. They smell the fumes, too. But if you look closely, you won’t see them gasping or coughing. That’s only because bees don’t have lungs. I just read a study about exhaust fumes affecting plants, so I’m less worried about the bees’ trachea and their spiracle outlets than I am about all the flowers and their ability to attract pollinators.
Researchers planted some mustard seeds in a greenhouse, then added the equivalent of a Hummer to the mix. The pollution does something odd to scents given off by blossoming mustard. At a distance of 4.5 metres (15 feet), scent molecules from Brassica nigra (black mustard) are about one-third fewer. They have disappeared by combining with the ozone and turning into something that’s not attractive to bees. Maybe it’s a boiled cabbage odour, I don’t know, but ozone interferes with a flower’s natural scent.
Oddly, close to the flower, there is no discernible reduction in the scent, even with the ozone as dense as it is four metres away. Further away, the concentration of the nice flowery scent falls more quickly than it does in clean air. This spells trouble for bees. Especially bumblebees, which are guided more by their nose than any instructions they may receive from their buddies back at the hive. Honey bees are less affected than wild indigenous bumblebees because honey bees fly further and depend on scent less than most other bees do.
What’s the solution? It looks like we may be headed towards cleaner air, especially with the popularity of electric cars (if they are powered by renewable sources, not coal). That will help the bees. And us, too, if we are stuck in traffic on a busy highway.